Yes, as many have stated, short runs of loudspeaker cable are often best. To be practical I would say 3 meters or shorter if possible. But the real world often dictates otherwise.
I would like to offer that keeping single ended interconnects (SEI) to 1 meter or so is not a hard or fast rule. This is dependent on several factors. My preamplifier has an output impedance of a rather low 200 ohms and is capable of driving long SEI if required. In my initial room setup, I had interconnects to my mono blocks about 2 meters long. After changing my room, I now have a 25-foot pair of interconnects to my mono blocks with absolutely no issue(s). All my other interconnects are 1-meter pairs and a 2.5-meter pair.
Some people who have gone all digital without a stand-alone preamplifier may use balanced XLR interconnects.
Just making this point for whatever it may be worth.